e coli cell lysis

does anyone here encounter the problem before that genes orignating from different organisms will effect the efficiency of e coli cell lysis? I am experiencing this problem right now. some of my genes from spefic species introduced into e coli but i can not break cell to get the enzyme extract by sonication, sometimes even using the lysozyme at first. What can I do to solve this problem? I hope someone here can give me some suggestions. Thanks in advance.

Are you shore that you have E.coli cells?You might have a contamination of some sort (like yeast).

Thanks for your reply, molgen.If there are some contamination, it should not be yeast. I checked under the microscope. They look like bacteria. But I can not identify whether they are e coli or not.If there is no contamination, what should I do?

Are you shore that you have E.coli cells?You might have a contamination of some sort (like yeast).

Thanks for your reply, molgen.If there are some contamination, it should not be yeast. I checked under the microscope. They look like bacteria. But I can not identify whether they are e coli or not.If there is no contamination, what should I do?

I forgot that I had a positive control and it always worked as expected.